CNG Base Training2

7/28/2019 CNG Base Training2

http://slidepdf.com/reader/full/cng-base-training2 1/74

CNG

Base training



Summary (I)

1. CNG: physical and chemical properties. 2. CNG and environment.

3. CNG equipment.1. Equipment structure.

2. The mechanical components.1. Cylinder.

2. Cylinder valve.

3. Filling unit.

4. High pressure pipes and fittings.

5. Pressure gauge.

6. Pressure reducer.

7. Petrol solenoid valve.

8. Mixer.

9. Power screw.



Summary (II)

3. The electronic components.1. Sunny ECU.

2. Change over switch.

3. Injector emulators.

4. Spark advancers.

4. System tuning.



CNG – Chemical and physical properties

• CNG = Compressed Natural Gas.

• Composition depends from the CNG origin.• CNG gas mixture: methane (CH4)

nitrogen (N2)carbon dioxide (CO2)

• Mercaptanes added to give smell





CNG and environment

CNG pollution VS. petrol pollution.

• Less carbon monoxide (CO) poisonous

• Less 22% carbon dioxide (CO2) global warming

• No lead presence poisonous

• Less poisonous unburned hydrocarbons (HC)



Equipment structure



Cylinder



Cylinder



Cylinder valve



Cylinder valve – Manual valve closed



Cylinder valve – Manual valve open



Cylinder valve – Excess flow valve closed



Cylinder valve – Venting holes



Cylinder valve – Safety devices



Cylinder valve – Burst disc



Cylinder valve – Fuse plug



Filling unit



Filling unit – Charge phase



Filling unit – Non return valve close



High pressure pipes and fittings

• Steel pipes (burst pressure > 800 bar).

• M12 fittings for BRC components.• Dedicated BRC ferrules.

• Periodical leakage test on fittings (water & soap).

• Ferrule has to be correctly fixed on the pipe.



Pressure gauge



Pressure gauge



CNG 3 stage reducer



CNG reducer – First stage



CNG reducer – First stage closed



CNG reducer – First stage open



CNG reducer – Pressure relief valve closed



CNG reducer – Pressure relief valve open



CNG reducer – From the first to the second stage



CNG reducer – Second stage



From the second to the third stage – solenoidvalve closed



From the second to the third stage – solenoidvalve closed



From the second to the third stage – solenoidvalve open



From the second to the third stage – solenoidvalve open



CNG reducer – Third stage



CNG reducer – Third stage



Third stage – Idle +close



Third stage – Idle +open



Third stage – Sensibility +close



Third stage – Sensibility +open



CNG reducer - Water circuit



Petrol solenoid valve



Petrol solenoid valve



Mixer and power screw – engine in low load

Mixer and power screw engine in full load and



Mixer and power screw – engine in full load andpower screw +open

Mixer and power screw engine in full load and



Mixer and power screw – engine in full load andpower screw +closed



Sunny ECU - Functions

• Switch over.• Safety.

• Pressure gauge reading.



Sunny ECU – Electrical connections scheme



Micro switch - Functions

• Drive the main ECU for theswitch over.

• Fuel kind indication (bicolourled).

• Pressure indication (4 led).



Micro switch – Switch over function

Petrol mode.

• Switch pushed in the “petrol pump” position.

• Rectangular LED's colour: red

Switch from petrol to CNG.

• Push the switch in the middle position.

• Rectangular LED's colour: switched off

• Wait the empty of the carburettor.

• Push the switch in the “BRC” position.

• Rectangular LED's colour: green



Micro switch – Switch over function

CNG mode.

• Switch pushed in the “BRC” position.

• Rectangular LED's colour: green

Switch from CNG to petrol.

• Push the switch in the middle position.

• Rectangular LED's colour: yellow

• Wait the filling of the carburettor.

• Push the switch in the “petrol pump” position.

• Rectangular LED's colour: red



Injector emulator Modular HI MM - Function

Petrol mode.• The petrol ECU continue to drive

the petrol injector.

• The relé in the injector emulator

is in the normally closed position.

CNG mode.

• The petrol ECU drive the coil in

the injector emulator.• The petrol injector stay close.

• The relé in the injector emulatoris in the open position.

Injector emulator Modular HI MM



Injector emulator Modular HI MMElectrical connections scheme

• Green wire to the white/green from the ECU.

• Black wire with the black of the ECU.

• Red wire to the battery 12 V, under 7,5 A fuse.

Injector emulator Modular HI MM



Injector emulator Modular HI MMElectrical connections scheme

• Cut thenegative wireof the petrolinjectors.

• Connect theorange wire tothe injectorside.

• Connect the

violet wire tothe petrol ECUside.

S k d B i f



Spark advancer – Basic features

• Change, increasing, the spark advances in CNG

mode.• Hold the original spark advances in petrol mode.

• Increase the torque and the power in CNG mode.

• Reduce the exhaust temperature in CNG mode.



A A t



Agena - Antares

• Led on = advanceconnected.

• Spark advance setting by

micro-switches.• Emergency red connector

in case of spark advancerfailure.

A A t



Agena - Antares

Micro-switches setting

• Cylinder number: set switches 1 & 2

• Advance degree: set switches 3 & 4

• Advance operating conditions: set switches 5 & 6

A i A S t



Aries - Acroux - Santro

Aries, Acroux & Santro work as

spark advancer in CNG mode.

It advance the crankshaft signal

in input to the petrol ECU.

t

Crankshaft signal from the sensor (schematic)

t

Crankshaft signal to the petrol ECU

6°15°

A i A S t



Aries – Acroux - Santro

• Led on = advance connected.• Advance intervention in idle and cut-off conditions

adjustable by operating on a screw.

• Spark advance setting by micro-switches.

• Emergency connector in case of spark advance failure

Pegaso



Pegaso

Pegaso works as spark retarderin petrol mode.

The correct spark advance in

CNG is obtained adjusting the

distributor position.

In petrol mode Pegaso works

retarding the spark to obtain the

original value.

Pegaso



Pegaso

• Register to set thespark advance onpetrol to the originalvalue.

• Emergency connectorin case of spark advance failure

System tuning – Engine in idle load and idle



y g gscrew +close




y g gscrew +close




y g gscrew +open




screw +open

System tuning – Engine in partial load and



sensibility screw +closed




sensibility screw +closed




sensibility screw +open




sensibility screw +open

System tuning – Engine in full load and power



screw +closed

System tuning – Engine in full load and power



screw +open

Mixer + Power screw + Reducer

Th i l fl h i i



Theorical flow characteristic

Air mass flow

CNG mass flow

C G ( / ) 2

idle

Full load & Max RPM

Power screw setting area

Sensibility screw setting area

Idle screw setting area

CNG Base Training2

Documents